"We believe that messaging is a key technology in cloud computing," SpringSource general manager Rod Johnson tells The Reg. "As applications move from the traditional enterprise setup behind the firewall into public and potentially hybrid clouds, those applications will need messaging as a fundamental building block to communicate with each other."

A "public cloud" would be something like Amazon's EC2 web service, which provides world+dog with on-demand access to scalable server power, and a "hybrid cloud" would a similar setup that also spans resources inside a private data center.

SpringSource was recently acquired by VMware, whose hypervisors underpin such infrastructure services. VMware is working to build an "ecosystem" of partner clouds through its vCloud program, and SpringSource, the company says, is part of its effort to help companies deploy their applications across these and other sky-high services.

Rabbit Technolgies CEO Alexis Richardson tells us that the company's open source messaging system, dubbed RabbitMQ, is used by NASA's Nebula project, a private infrastructure cloud that will apparently be used to power applications across the US federal government. Nebula is based on Eucalyptus, the open source platform that mimics Amazon EC2 inside your own data center, and according to Richardson, RabbitMQ is used to communicate between virtual machines and to push information down to end user browsers.

"Imagine you have a VM and you don't know where it is. It's just some virtual resource in the cloud. It's just in one of many containers in a massive data center," Richardson says. "How do you get the right information to the right VM to execute the right command for the right user at the right time? The answer is messaging."

The messaging system also underpins a procurement system run by the US Army, and it will be used by Apps.gov, a new online storefront that serves government agencies. SpringSource declined to discuss specific cases where RabbitMQ is used in tandem with the company's Java framework. "We're not really at liberty to talk about it, because most of the common usage is in the financial sector, and those guys tend to be a little secretive," Johnson says.

But Rabbit's Ricahrdson points to NPC International, the world's largest Pizza Hut franchisee, as an outfit that has married SpringSource and RabbitMQ.

RabbitMQ is based on the free and open AMQP standard, a messaging setup originally developed by JP Morgan, and it's open sourced under the Mozilla license.

Terms of SpringSource's Rabbit deal were not disclosed. Rabbit will be folded into VMware's SpringSource division, and its engineers will report into SpringSource R&D, which is a separate entity. Johnson says the acquisition reinforces VMware's commitment to open source.

"This is evidence of the seriousness with which VMware takes open source," he says. "We believe openness is an important part of cloud computing. We think it's very important that organizations do not get locked into particular platforms." ®